A. Field of the Invention
The present invention relates to a novel method and arrangement for setting and retrieving multiple packers in a multi-zone well through the use of a flapper valve to control flow in and through the packers.
B. Description of the Prior Art
It is well known to use packers to isolate various zones of a well. One such arrangement is shown in U.S. Pat. No. 6,315,044 to Tinker, which is incorporated herein by reference. FIGS. 13 and 14 of the Tinker patent show multiple pre-milled “windows” in the casing of the well to facilitate lateral drilling from the main well bore. While shown nearly adjacent to each other in the drawings, these ports can be a great distance from each other, even thousands of feet. It is usually desirable to isolate one zone from another so that operations may be performed on one particular zone, especially when one zone is worked prior to beginning work on the next zone.
One of the difficulties in working wells is the fact that they are subterranean and not directly accessible by the operators of the well. Many methods have been devised to set and release packer tools to isolate zones of a well bore casing. See for instance U.S. Pat. No. 5,197,547 issued Mar. 30, 1993 to Allen B. Morgan. In Morgan, a combination of shear pins, spring tools, and J slots are used to control insertion, setting, and retrieval of the tools. Through sequential release of the shear pins and springs, a top slip body and a lower drag body are moved in contact with a packer body thereby expanding the packers to seal a zone in a well bore. Likewise a series of shear pins or j tools are used to release the packers during sequential trips of the retrieving tool into the wellbore.
The current invention proposes an arrangement and method for perforating multiple zones in a well bore through the use of multiple packers which can be individually (sequentially) released and retrieved in a single trip.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.